int *sumZero(int n, int *returnSize)
{
    int i;
    int *a = (int *)malloc(n * sizeof(n));
    for (i = 0; i < n / 2; i++)
        a[i] = i + 1;
    for (i = n / 2; i < n; i++)
        a[i] = -a[i - n / 2];
    if (n % 2 == 1)
        a[n - 1] = 0;
    *returnSize = n;
    return a;
}